Kaolinite Particle Sizes in the <2 µm Range Using Laser Scattering

Abstract

Al~tract--The Clay Minerals Society Source Clay kaolinites, Georgia KGa-1 and KGa-2, have been subjected to particle size determinations by 1) conventional sedimentation methods, 2) electron microscopy and image analysis, and 3) laser scattering using improved algorithms for the interaction of light with small particles. Particle shape, size distribution, and crystallinity vary considerably for each kaolinite. Replicate analyses of separated size fractions showed that in the <2 pm range, the sedimentation/ centrifugation method of Tanner and Jackson (1947) is reproducible for different kaolinite types and that the calculated size ranges are in reasonable agreement with the size bins estimated from laser scattering. Particle sizes determined by laser scattering must be calculated using Mie theory when the dominant particle size is less than -5 urn. Based on this study of two well-known and structurally different kaolinites, laser scattering, with improved data reduction algorithms that include Mie theory, should be considered an internally consistent and rapid technique for clay particle sizing.

Experimental Transformation of Kaolinite to Halloysite

“…All samples are analyzed using a Siemens D5000 diffractometer with graphite monochromator and CuKet radiation. Particle size distributions are measured by laser scattering in a flow-through cell using a Malvern Mastersizer E instrument and methodology described by Mackinnon et al (1993).…”

Kaolinite: NMF Intercalates

“…The aqueous suspension was then separated into 6 size fractions: >2 #m, 0.6-2 #m, 0.5--0.6 #m, 0.4-0.5 #m, 0.3-0.4 #m, and <0.3 #m following the method outlined by Tanner and Jackson (1947). The study by Mackinnon et al (1993) describes a method for estimation of the size range(s) for each fraction using a laser scattering technique. Each size fraction was dried in an oven at 120~ and subsequently weighed on a Metier balance to provide a value for the wt.…”

“…In general, this technique is the preferred method for particles >0.1 ~zm provided an appropriate model is used for the scattering of light from small particles. Details of these size distribution methods are given by Mackinnon et al (1993). Particle size distributions for the range 0.1-80 #m were determined by laser scattering in a flow-through cell using a Malveru Mastersizer E with samples stirred in a 25 ml water suspension containing 3 ml of 10% Calgon solution.…”

“…Particle size distributions for the range 0.1-80 #m were determined by laser scattering in a flow-through cell using a Malveru Mastersizer E with samples stirred in a 25 ml water suspension containing 3 ml of 10% Calgon solution. On average, greater than 105 particles were measured by this laser scattering technique per sample analysis (Mackinnon et aL, 1993). In cases where replicate analyses of a specific parameter have been determined (e.g., HI values), the mean value is reported with an estimated standard deviation to the last significant figure given in parentheses.…”

“…Variations in crystallographic parameters with particle size have been assessed for few kaolinites to date. This lack of data is perhaps due to the difficulty of obtaining precise estimates of particle size in the <2 #m range, although Tanner and Jackson (1949) developed useful methods that are quite reproducible (Mackinnon et al, 1993).…”